An antenna for a motor vehicle is described in the German patent document DE 295 00 961 E1. This antenna has a base plate or base body composed of metal and which carries antenna elements, for example a strip-conductor antenna. To protect the antenna elements which can be mounted on that base plate, an antenna housing, which can be composed of a nonconductive material like, for example, a synthetic resin material, is provided on the base plate to enclose those elements.
The base plate can be a threaded pin which can be inserted into a hole in the vehicle body and which can enable the antenna assembly to be affixed on the vehicle body. The fixing means can be, for example, a nut which is threaded onto the pin or bolt and the base plate can lie parallel to a wall of the vehicle body, for example, a roof so as to abut the latter when the nut is tightened onto the bolt.
This prior system has a drawback in that water or moisture can penetrate through the opening into the interior of the vehicle body and the penetration of moisture can affect any electronic elements which are provided beneath the assembly. In the past electronic elements like amplifiers and the like have been provided below such base body. The penetration of moisture or liquid water can adversely affect electronic components to the point that signals cannot be received by the antenna. Of course the penetration of water or moisture into the interior of the vehicle has other drawbacks as well.
The problem could not be resolved with conventional antennae which utilize base bodies of metal. However, substituting base bodies of other materials has not been found to be practical since a fixed and rigid mounting of the assembly has been necessary. Leakage can cause rusting of the metal body of the vehicle where the assembly is mounted and can cause rusting or contamination of the antenna elements as well.